This invention relates to a self adhesive tape and more particularly to a dry wallboard seam and corner tape.
Tapes of this type are used primarily in building construction and/or repair and the erection of dry walls. These tapes are usually applied to seal the seams between sections of wallboard on the flat wall surfaces or at corners.
There is currently a need to provide as total a seal as possible between sections of wallboard and to provide as smooth a covering as possible on butt corners of walls. Furthermore, such seal must be as flush as possible with the sections of the wallboard itself and must be strong enough so as to not release from the seam and bulge out. In corner applications, it is necessary that the corner seam be sealed totally with a material which will not bunch up or tear, thus breaking the seal. Such seal must also be unaffected by the long term environment found in typical areas of application.
In attempting to meet these requirements the prior art has used various approaches. The most common approach is to apply a bedding coat of gypsum compound directly over the seam where sections of wallboard meet, then to apply a tape over the coat of gypsum compound and then to apply one or more coats of gypsum compound over the tape.
This procedure requires several days to elapse before the wall is ready for painting, papering, or finishing. The time and labor costs involved increase the costs of the construction.
One of the principal advantages of this invention is the elimination of the need for the bedding coat of gypsum compound with the attendant savings in material and labor costs and time.
Using an open mesh fiber glass material to seal the seams between the sections of wallboard, as disclosed in U.S. Pat. No. 3,391,037 to McNulty, is also unsatisfactory because of the washboard like ridges typically resulting in practice when this open mesh fiber glass product is overcoated with the gypsum compound.
In the prior art there are devices which apply the gypsum compound and the tape simultaneously, but these devices are cumbersome to use and unreliable in operation.
Another problem encountered in using a current state of the art approach is that the adhesive on the tape sometimes tends to bleed out from the edges of the tape thus weakening the seal. Also, the adhesive coating on the tape tends to lessen the bond between the tape itself and the coat of gypsum compound applied over the tape to finish the point. This can result in the tape coming loose from the wall thus breaking the seal between the wallboard sections.